Update headers for three20 support.

Add keyPath support to the object loader.

Code/ObjectMapping/RKObjectLoader.h

@@ -36,6 +36,7 @@
 	RKResponse* _response;
 	Class<RKObjectMappable> _objectClass;
 	NSFetchRequest* _fetchRequest;
+	NSString* _keyPath;
 }
 
 /**
@@ -96,6 +97,12 @@
  */
 @property (nonatomic, retain) NSFetchRequest* fetchRequest;
 
+/*
+ * The keyPath property is an optional property to tell the mapper to map a subset of the response
+ * defined by a specific key.
+ */
+@property (nonatomic, copy) NSString* keyPath;
+
 /**
  * Return an auto-released loader with with an object mapper, a request, and a delegate
  */

Code/ObjectMapping/RKObjectLoader.m

@@ -20,7 +20,7 @@
 
 @synthesize mapper = _mapper, delegate = _delegate, fetchRequest = _fetchRequest,
 			request = _request, response = _response, objectClass = _objectClass,
-			source = _source;
+			source = _source, keyPath = _keyPath;
 
 + (id)loaderWithMapper:(RKObjectMapper*)mapper request:(RKRequest*)request delegate:(NSObject<RKObjectLoaderDelegate>*)delegate {
 	return [[[self alloc] initWithMapper:mapper request:request delegate:delegate] autorelease];
@@ -42,6 +42,7 @@
 	[_request release];
 	[_response release];
 	[_fetchRequest release];
+	[_keyPath release];
 	[super dealloc];
 }
 
@@ -176,7 +177,7 @@
 		}
 	} else {
 		
-		id result = [_mapper mapFromString:[response bodyAsString] toClass:self.objectClass];
+		id result = [_mapper mapFromString:[response bodyAsString] toClass:self.objectClass keyPath:_keyPath];
 		if ([result isKindOfClass:[NSArray class]]) {
 			results = (NSArray*)result;
 		} else {

Code/ObjectMapping/RKObjectManager.m

@@ -108,6 +108,7 @@ static RKObjectManager* globalManager = nil;
 	
 	NSURL* URL = [self.client URLForResourcePath:resourcePath];
 	RKRequest* request = [[[RKRequest alloc] initWithURL:URL] autorelease];
+	[self.client setupRequest:request];
 	RKObjectLoader* loader = [RKObjectLoader loaderWithMapper:self.mapper request:request delegate:delegate];
 	loader.objectClass = objectClass;
 	

Code/ObjectMapping/RKObjectMapper.m

@@ -101,8 +101,11 @@ static const NSString* kRKModelMapperMappingFormatParserKey = @"RKMappingFormatP
 	return result;
 }
 
-- (id)mapFromString:(NSString*)string toClass:(Class)class {
+- (id)mapFromString:(NSString*)string toClass:(Class)class keyPath:(NSString*)keyPath {
 	id object = [self parseString:string];
+	if (keyPath) {
+		object = [object valueForKeyPath:keyPath];
+	}
 	if ([object isKindOfClass:[NSDictionary class]]) {
 		return [self mapObjectFromDictionary:(NSDictionary*)object];
 	} else if ([object isKindOfClass:[NSArray class]]) {